Transgenic construct used to study the 1A2 insulator. Consists of the y wing enhancer, the w eye enhancer, the y body enhancer, a loxP cassette containing a 236bp subfragment of the '1A2' insulator (su(Hw)BR-y-AS-C, an endogenous insulator containing su(Hw)-binding sites which is found between the y gene and the ac-sc complex) containing the su(Hw)-binding sites but not the Cp190-binding region or the region homologous to jockey, the y transcription unit (including the y bristle enhancer located downstream of the transcription start site) and the w gene.